A two way radio is a communication device which is capable of both transmitting and receiving information from other communication devices. A mobile phone or a cellular telephone is an example of a two-way radio that both transmits and receives information at the same time i.e. full-duplex communication. Conventionally, a two way radio, hereafter radio, operates on fixed Radio Frequency (RF) channels, which are the physical resources over which information or content is sent between communication devices. Generally, in both analog and digital wireless communications a carrier signal of suitable frequency is modulated by a baseband signal which represents information/content to generate a modulated signal. The modulated signal is transmitted to the radio on an appropriate RF channel.
Generally, a radio receiver scans a plurality of channels to detect the presence of a signal at the carrier frequency, hereafter carrier. In both analog and digital wireless communication systems, carrier detection is a key for efficient and interference free operation of multiple radios within the communication system.
Accordingly, there is a need for a method and apparatus for detecting presence of a carrier in a signal received by a device.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of various embodiments.
The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Thus, it will be appreciated that for simplicity and clarity of illustration, common and well-understood elements that are useful or necessary in a commercially feasible embodiment may not be depicted in order to facilitate a less obstructed view of these various embodiments.